A double multi-vane type rotary fluid machine system is described in Japanese Patent Application Laid-open No. 59-41602. In this rotary fluid machine system, a circular vane-supporting ring is disposed between an elliptic outer cam ring and an elliptic inner cam ring, and outer and inner ends of a plurality of vanes radially slidably supported on the vane-supporting ring are in abutment against an inner peripheral surface of the outer cam ring and an outer peripheral surface of the inner cam ring, respectively. Therefore, when the vane-supporting ring is rotated relative to the outer cam ring and the inner cam ring, the volumes of a plurality of vane chambers partitioned by the vanes between the outer cam ring and the vane-supporting ring are increased or decreased and in this manner, the rotary fluid machine system functions as an expander or compressor. In addition, the volumes of a plurality of vane chambers partitioned by the vanes between the inner cam ring and the vane-supporting ring are increased or decreased and in this manner, the rotary fluid machine system functions as an expander or compressor.
In this double multi-vane type rotary fluid machine system, the outer and inner rotary fluid machines can be used as independent expanders, respectively; the outer and inner rotary fluid machines can be used as independent compressors, respectively; and one and the other of the outer and inner rotary fluid machines can be used as an expander and a compressor, respectively.
A vane-type rotary fluid machine system capable of being used as an expander or a compressor is described in Japanese Patent Application Laid-open No. 60-206990. In this rotary fluid machine system, a circular intermediate cylinder is disposed eccentrically between a circular outer cam ring and a circular inner cam ring disposed concentrically with each other, and outer and inner ends of a plurality of vanes radially slidably supported in the intermediate cylinder are in abutment against an inner peripheral surface of the outer cam ring and an outer peripheral surface of the inner cam ring, respectively. Therefore, when the intermediate cylinder is rotated relative to the outer cam ring and the inner cam ring, the volumes of a plurality of vane chambers partitioned by the vanes between the outer cam ring and the intermediate cylinder are increased or decreased and in this manner, the rotary fluid machine system functions as an expander or a compressor. In addition, the volumes of a plurality of vane chambers partitioned by the vanes between the inner cam ring and the intermediate cylinder are increased or decreased and in this manner, the rotary fluid machine system functions as an expander or a compressor.
In this vane-type rotary fluid machine system, the outer and inner rotary fluid machines can be used as independent expanders, respectively; the outer and inner rotary fluid machines can be used as independent compressors, respectively; and in addition, the outer and-inner rotary fluid machines can be connected in line to each other and operated as a two-stage expander or a two-stage compressor by allowing a working fluid passed through one of the outer and inner rotary fluid machines to be passed through the other rotary fluid machine.
A radial plunger pump is described in Japanese Patent Application Laid-open No. 64-29676. In this pump, a plurality of cylinders are defined radially in a rotor disposed eccentrically in a circular cam ring, and plungers are slidably received in the cylinders with their tip ends abutting against an inner peripheral surface of the cam ring, so that the plungers are reciprocally moved and operated as a pump.
It should be noted here that one embodiment of a rotary fluid machine is considered, in which pistons are slidably supported in a plurality of cylinders disposed radially in a rotor, and rollers mounted on the pistons are engaged in elliptic annular grooves defined in an inner peripheral surface of a casing, so that a pressure energy of a working fluid flowing into and out of the cylinders and a mechanical energy for rotating the rotor are converted from one into another by converting the reciprocal movement of the pistons and the rotational movement of the rotor from one into another by the engagement of the rollers and the annular grooves with each other.
The rollers in such rotary fluid machine are urged against walls of the annular grooves by the pressure and centrifugal force of the working fluid acting on the pistons and hence, there is a possibility that the durability of the rollers repeatedly receiving reaction forces from the annular grooves may be degraded.